The synchronized motion of fish in a school is an example of coherence. Similar principles apply at the quantum mechanical level, where coherence exists on the molecular scale, such as in the motion of electrons in molecules. In a Nature review article, experts summarized the state of scientific research on coherence and its potential for yielding striking new functions in complex chemical systems. They also envisioned how scientists might be able to use coherence to improve specific functions, for instance, production of solar fuels.
The article reviews scientific discoveries of the presence and potential role of coherence in chemical and biochemical systems. Also, it examines opportunities to harness coherence. Why? Coherence could enhance energy transduction and chemical transformation, such as in light-driven reactions. Such insights could help create new ways to generate and use energy.
In the world around us, it’s easy to see orders and patterns, such as the collective movement of a flock of birds. These patterns, or coherence, also exist on the molecular scale. For example, scientists see coherence in the ultrafast collective motions of molecules in liquids or the bonding structure of benzene rings. On both the macroscopic and microscopic scales, coherence and function appear to be connected. Scientists want to understand in more detail how function and coherence may be linked and then, by building on this knowledge, potentially use coherence as a tool in designing or improving function in chemical systems that generate or use energy. Until recently, scientists considered classical and quantum mechanical coherence to be fragile events, but new studies may shift that viewpoint. In a Nature review article, 19 scientists surveyed recent scientific discoveries related to coherence and discussed how that work suggests coherence in chemical and biological systems can be a robust phenomenon that survives in the face of chaos and noise. They also explored how coherence could change how we design complex chemical systems to improve function, for instance, in photosynthetic mimics that harvest light and convert it into a another form of energy such as fuels or electricity.
The Division of Chemical Sciences, Geosciences, and Biosciences, Office of Basic Energy Sciences, Office of Science, Department of Energy funded the review article.
G.D. Scholes, G.R. Fleming, L.X. Chen, et al., “Using coherence to enhance function in chemical and biophysical systems.” Nature 543, 647 (2017). [DOI: 10.1038/nature21425]